Mobile outriggers for scaffolds in the prior art have been relatively heavy, complicated, and difficult to maneuver, particularly around building corners where the rotation operation typically requires the efforts of at least two persons.
A search of the patent literature discloses a number of mobile or portable outriggers and other mobile devices. For example, U.S. Pat. No. 3,854,550 illustrates a mobile outrigger for scaffolds. The outrigger is in the form of a pair of transversely spaced trucks. Each truck is wheeled on casters and permits movement of the scaffolds laterally and vertically as well as toward or away from the building. The outrigger system constitutes very heavy equipment and is such that the beams on each of the outriggers can be telescoped out away from the building far enough so that the scaffolding can be maneuvered around a building corner.
U.S. Pat. No. 4,096,922 discloses an outrigger system in which leg supports depend from a beam and make contact with the roof. At a location inwardly of the leg supports, the outrigger beam is secured to an elevated support rail in a manner to permit both axial, sideways, and angular movement for proper positioning of the outboard end of the beam relative to the side of a building.
U.S. Pat. No. 4,274,507 shows a portable support for a scaffold comprised of first and second wheeled support members. An electric motor is provided on one of the support members to drive the first and second support members as a unit along a building roof.
The following list includes the additional patents found in the search:
U.S. Pat. No. 1,616,769 PA1 U.S. Pat. No. 2,430,179 PA1 U.S. Pat. No. 2,604,359 PA1 U.S. Pat. No. 2,775,488 PA1 U.S. Pat. No. 3,130,813 PA1 U.S. Pat. No. 3,537,545 PA1 U.S. Pat. No. 3,957,204 PA1 U.S. Pat. No. 4,142,548